Method and apparatus for recovering juice from sucrose bearing materials

ABSTRACT

Sucrose bearing materials, such as raw sugar cane, are shredded and then subjected to application of maceration liquid to penetrate the liquid into the ruptured cells of the material. Following this operation, the saturated material is conveyed through a mechanical screw press having sequentially arranged drainage cage sections in each of which juice combined with maceration liquid is expressed from the material. The material leaving the press is subjected to a further treatment with maceration liquid, preferably fresh maceration water, and then the material is processed through the dewatering stage, such as a high pressure dewatering screw press, after which the spent bagasse is disposed of in any suitable manner. In the first screw press, the liquids extracted at various points in the sequential cage sections are recirculated in countercurrent fashion to preceding stages of the press, and liquids from the first stage of the press are recirculated to the material entering the press from the shredding stage.

United States Patent 15] 3,661,082 French et al. [4 1 May 9, 1972 [54] METHOD AND APPARATUS FOR 3,016,818 l/l962 Barreto ..100/75 RECOVERING JUICE FROM SUCROSE 3,133,835 5/1964 Steckel 1 127/45 BEARING MATERIALS 3,275,472 9/1966 Tantawi et al. ..l27/45 X [72] Inventors: Alfred W. French; Forest J. Starrett, Jr., Primary Examiner-Walter A. Scheel both of Piqua, Ohio Assistant Examiner-Alan I. Cantor [73] Assignee: The French Oil Mill Machinery Company, Atmmey Marechal Blebel French & Bugg Piqua, Minami County, Ohio ABSTRACT [22] Filed: Dec. 18, 1969 Sucrose bearing materials, such as raw sugar cane, are [2l] Appl. No.: 886,178 shredded and then subjected to application of maceration liquid to penetrate the liquid into the ruptured cells of the 7 material. Following this operation, the saturated material is Cl g% k g g gsi gfig conveyed through a mechanical screw press having sequen. [5]] Int Cl 8310b 9/14 tially arranged drainage cage sections in each of which juice 58] Fieid I 17 127 combined with maceration liquid is expressed from the b 123/ material. The material leaving the press is subjected to a further treatment with maceration liquid, preferably fresh References Cited maceration water, and then the material is processed through the dewatering stage, such as a high pressure dewatering screw UNITED STATES PATENTS press, after which the spent bagasse is disposed of in any suitable manner. In the first screw press, the liquids extracted at 3,086,452 4/1963 French 100/75 various points in the sequential cage sections are recirculated 3,100,725 8/ l 963 Smart 127/43 in countercurrent fashion to preceding stages of the press, and 1346594 7/1920 f f loo/75 liquids from the first stage of the press are recirculated to the 33551260 I [/1967 Brumche'olsen loo/75 x material entering the press from the shredding stage. 3,420,708 l/l969 Schaffer 127/45 X 1,688,904 10/1928 Vazquez 127/45 Claims, 2 Drawing Figures FRESH WATER I3 39 33 44 H2 I i k 84 j l Ill O 06 "'fl I I I l 5 10a '00 5 lzl 90d. F 900 I22 l32 sob I24 TO BOILING HOUSE METHOD AND APPARATUS FOR RECOVERING JUICE FROM SUCROSE BEARING MATERIALS CROSS-REFERENCE TO RELATED APPLICATION Certain aspects of this invention are related to the method and apparatus disclosed in copending application Ser. No. 648,744, filed June 26, 1967, now U.S. Pat. No. 3,552,304 issued Jan. 5, 1971, entitled Process and Apparatus for Treating Sucrose Bearing Materials, which is assigned to the same assignee as this application.

BACKGROUND OF THE INVENTION Various screw press devices have been used successfully for continuous processing of sucrose bearing materials to recover large amounts of the juice therefrom, without using the conventional, well-known, roller mill arrangements. Typical of these devices are those disclosed in U.S. Pat. Nos. 3,086,452 and 3,1 1 1,080, both of which issued to the assignee of this application. The present invention relates to an improvement, particularly with respect to the type of apparatus and method disclosed in said U.S. Pat. No. 3,111,080.

In order to recover as high a concentration of sucrose from the sugar cane, it is desirable to rupture as many of the cells of the cane during the initial crushing and shredding operation as is possible, and to saturate the material with a maceration liquid which will thus penetrate into the ruptured cells and effectively leach or flush the encapsulated juice, which bears the sucrose, from the cells of the cane. In general, countercurrent flow arrangements, whereby fresh maceration water or liquid is introduced in the discharge of the system and extracted juices of higher and higher concentration are pumped in countercurrent fashion through the system, are broadly known. An elementary type of arrangement, using dilute aqueous sugar juice, and employing a battery of screw presses, is disclosed in U.S. Pat. No. 3,100,725. countercurrent flow of maceration liquid is also disclosed in some elementary aspects in the aforementioned U.S. Pat. No. 3,086,452. However, these systems do not achieve the complete and continuous type of countercurrent flow of maceration liquid which is desirable in order to maintain a continuous washing of juice from the sucrose bearing material during the entire operation.

SUMMARY OF THE INVENTION According to the present invention, the cane, or similar sucrose bearing cellular material, is prepared by cutting it into suitable short lengths for convenient handling, and crushed to remove an initial flow of raw juice. The crushed cane is then processed through a shredder, for example, a conventional hammer-mill shredder, and during or immediately following this shredding operation the raw juice may be added as maceration liquid. Alternatively, the raw juice may be sent directly to the boiling house, and maceration liquid obtained from a later stage of the system. Along with this liquid, or immediately after it, the last of a series of countercurrent flow circuits conveys other maceration liquid through the processed material. The shredded material is flooded with this maceration liquid to obtain effective penetration of the liquid into the ruptured cells. Immediately thereafter this material is conveyed in a continuous manner to the mechanical screw press of novel construction as hereinafter disclosed. The liquid drained from this shredded material is pumped to the boiling house where the sucrose is extracted from the liquid.

This screw press has a plurality of drainage cage sections arranged sequentially, each discharging into a sump or tank. From these sumps the expressed liquid is pumped to injection devices which introduce this liquid into an expansion chamber in the entrance to the preceding drainage cage section in the press. The processed material discharging from the press is conveyed to a conventional heavy duty dewatering screw press, or some form of mechanism, for pressing a substantial amount of the liquid from the spent bagasse, and during this conveying operation fresh maceration liquid is introduced, usually in the form of fresh water. This liquid flows through the bagasse, is collected, and pumped to the final drainage cage section, forming the first supply of maceration liquid which is then pumped in countercurrent fashion from one stage to the other in the multi-stage screw press. Liquid collected from the first or entrance drainage section of the multistage press is in turn pumped to and added to the amount of maceration liquid applied to the shredded material entering the press, as mentioned above.

An important feature of the present invention therefore is the provision of a special multi-stage screw press machine which continuously works and conveys the sucrose bearing material, while maceration liquid is continuously flowed and pressed in countercurrent fashion through this material. The operation results in a maximum amount of penetration of the cellular material by the maceration liquid, and hence an optimum removal of sucrose bearing juice from this material.

Accordingly, the principal object of the invention is to provide a method and apparatus as aforementioned, and particularly to provide in a continuous processing system for the removal of sucrose bearing juice from fibrous materials, a multi-stage mechanical screw press incorporating countercurrent liquid fiow circuits by means of which maceration liquid is continuously flowed through the material processed in the press in countercurrent fashion; to provide such a system wherein the materials supplied to the press is first shredded and subjected to flooding of maceration liquid, in order to obtain an initial full penetration of maceration liquid into the ruptured cells of the material; and to provide a novel multistage screw press machine for use in the system just described.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a complete processing system according to the invention; and

FIG. 2 is an enlarged detail view, partially in section, illustrating a portion of the screw press machine and the circuits through which countercurrent liquid flow is achieve.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1, raw sugar cane material C is fed by the conveyor 10 into a chopper l2 and then through a crusher 15 where an initial portion of the juice is released from the cane material and is collected within the receptacle 17. The crushed material is fed by the conveyor 20 directly into the inlet hopper 22 of a shredder 24.

The shredded material which is discharged from the shredder 24 is directed into a bin or hopper 25 formed at the lower end of an inclined drag conveyor 28. This conveyor includes a pair of endless chains 30 directed around sprockets 31 and carrying a series of laterally extending drag slats 32. The upper reach of the inclined conveyor is partially supported by an intermediate wall 33 extending between the upper conveyor housing wall 34 and lower wall 35.

A pair of manifolds 38 are mounted on the upper wall 34 in vertically spaced relationship and each manifold is adapted to receive a flow of maceration liquid as will be described later. These manifolds include openings 39 directing the maceration liquid through the bed of the material produced by a rotary leveling member 40 positioned in the hopper 25 in spaced relationship with the conveyor drag slats 32. A series of openings 42 are formed in the intermediate wall 33 generally opposite each group of manifold openings 39, and open into corresponding collecting pans 44 mounted on the underneath surface of the intermediate wall 33 for collecting the maceration liquid which filters through the bed of material.

The bed of material on the conveyor 28 is discharged into the inlet hopper 48 of a special mechanical screw press 50, details of which are shown in FIG. 2. The first or feed end section of this press, designated by the general reference numeral 52, surrounds a feed worm 53. and is made up ofa plurality of spaced apart screen bars 54. The worm may be interrupted at one or more locations, and in these interruptions radially adjustable breaker bars or lugs 55 are mounted extending toward the center of the feed worm, between its sections. As is well known these lugs provide resistance to rotation of the materia1, and assist in creating pressure upon the material which results in expression of liquids that drain through the spaces between the screen bars. The drive for this press is provided by a suitable motor 56 (FIG. 1) which is connected through a gearbox 57 to rotate a sleeve connection 58 that is connected to rotate the feed worm 53 at a predetermined higher speed, and also to rotate at a slower speed the internal shaft 59, which is shown as having a splined end extending into the transmission box.

The feed worm 53 conveys and discharges the material into the first of a plurality of dewatering or drainage cage sections 60a, 60b, 60c, and 60d. Within each of these sections there are worm members 6001, 60112, 60a3, etc. which are suitably connected to the shaft 59, as through a key (not shown) to rotate therewith at the slower speed and force material toward the discharge of the press which is defined by the discharge ring 64. This ring may be adjustable toward and away from the final drainage sections 60d to adjust the size of the annular discharge orifice. Between the worms in each section there are collars 66, and the final worm in each section, as 60a3, increases in size to a larger diameter on its downstream edge, this larger diameter being greater than the diameter of the succeeding collar. Radially outward, preferably spaced somewhat from the collars, there are breaker lugs or bars 68 which resist rotation of the material, and thus assist in the compaction and working of the material as it progresses from one worm to the next.

Downstream from the final worm 60d4 there is a discharge collar 69 which cooperates with the discharge ring 64 to define the discharge orifice from which the material exits the press. A nut 70 is fastened to the end of shaft 59 and holds the entire assemblage of worms and collars in place on the shaft. if desired, the collars may be free to rotate on the shaft as described in U.S. Pat. No. 3,092,017, and the discharge collar 69 may be mounted stationary on the press cage structure, also as disclosed in said patent.

The walls of the drainage cage sections are formed of screen bars 72 separated by suitable spacers (not shown) to define drainage slots or openings between the screen bars from which the liquid may flow. The assemblage of screen bars and spacers is mounted in inner replaceable cage inserts held in place by clamping bars with which the breaker lugs 68 may be integral, and the entire insert assembly is mounted within an outer split cage structure 78. At least one of the outer cages is arranged to swing to an open position on the longitudinal shaft 80 (FIG. 2) for opening and closing the press cage, for purposes of maintenance or repair.

In each of the cage sections there is provided one or more injector bars 82, extending radially inward towards the first collar in each section. A passage 83 extends through each of these bars, and is connected to a supply pipe 85. Thus, liquid flowing through these pipes discharges from the injector bars generally in the region where the material is expanding as it passes the larger diameter of the last worm in the section, and into the enlarged region at the entrance to the succeeding pressing state. This assists in absorption of the liquid by the material, as pressure on the material is substantially released during this operation.

The liquid expressed from the material and passing through the spaces between the screen bars, is collected in at least several separate sumps or bins 88, 88a, 88b, 88c, and 88d, corresponding to the feed or inlet section 52, and to the expression cage sections 60a-60d. The discharge from each of these sumps is directed to the inlet of a recirculating pump, these being designated at 90, 90a, 90b, 90c, and 90d, respectively. The outlets of the last three of these pumps are directed to the supply pipes 85 for the injector bars of the preceding stage, as shown schematically in FIG. 1. For example pump 904' is connected to the supply pipes for the injector bars in cage section 60c, and so on. The discharge from pump is connected to the manifold 38 on the lower end of the conveyor 28, and the discharge from pump 90a is connected to the upper manifold 38 at the top of this conveyor. Thus, maceration liquid expressed from, and drained away from, the final stages of the press is recirculated back through the material passing through the initial stages of the press. It should be understood that more sections, and additional circulating paths can be provided if desired, within the concept of the invention.

The material (bagasse) discharged from the countercurrent injection press 50 is directed onto a further conveyor provided with a leveling device 102 which forms a bed of predetermined thickness on the upper flight of the conveyor. This conveyor is likewise surrounded by housing 103, and provided with a lower manifold 105 having a corresponding collecting tank or pan 106 beneath the upper flight of the conveyor. This pan 106 is connected to the inlet of a pump 107 which in turn pumps the liquid into the injector bars of the last drainage section 60d. There is also an upper manifold 110 having a corresponding collection pan 111, which has its discharge connected to the inlet of the manifold 105. Fresh maceration water is supplied through line 112 into the upper manifold 1 10. The material discharged from the conveyor 100 is passed to the inlet hopper 115 of a further screw press machine 120, and liquid discharged in this second screw press passes through pipe 121 into a collection tank 122, and from that tank is recirculated by pump 124 through line 125 back to the lower manifold 105, being added to the liquid drained through the material into the upper pan 111.

The bagasse discharged from the press 120 has a relatively low moisture content, generally below approximately 50 percent moisture, and this bagasse can be burned as fuel, or put to other uses as may be desired.

The system provided by the invention, therefore, incorporates numerous countercurrent flows of maceration liquid, beginning with the fresh maceration water added to the upper manifold of the second conveyor, or progressing through the material, and through the several drainage sections of the press 50, thence through the bed of material on the first conveyor 30, with the liquid having the highest concentration of sucrose being derived from the pans 44, and flowing through line into a collecting tank 132, from which the liquid is pumped by the pump 133 to the boiling house or to the equipment by which the sucrose is derived from this liquid in known fashion.

Alternatively, raw juice from the receptacle 17 can be piped directly to tank 132, by adjusting the diverter valve 135, and in this condition maceration liquid to the shredder 24 can be obtained from the feed stage bin 88, via pump 90, by changing the diverter valve 137.

While the method herein described, and the form of apparatus for carrying this method into effect, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention.

What is claimed is:

1. The continuous process of treating sucrose bearing cellular fibrous material such as raw sugar cane or sugar cane bagasse to remove a high percentage of juice therefrom, comprising the steps of shredding the material to rupture its cells, applying maceration liquid to the shredded material to obtain effective penetration of the liquid into the ruptured cells, pressing the saturated material within a mechanical screw press having a plurality of sequentially arranged drainage cage sections thereby releasing juice combined with maceration liquid immediately as the material is compressed in each cage section, collecting the liquid separately from each cage sec tion, recirculating the collected liquid in countercurrent fashion back into the material passing through the preceding section, and collecting the liquid draining from the shredded material for extraction of sucrose.

2. A process as defined in claim 1 wherein said step of pressing includes pressing the material with progressively increasing pressure within each successive dewatering stage of the mechanical screw press.

3. A process as defined in claim 1 wherein the maceration liquid applied to the shredded material is that liquid collected from the initial drainage cage sections of the press.

4. A process as defined in claim 3 including the step of crushing the material prior to said shredding and thus removing an initial portion of juice from the material, and applying such initially removed juice as maceration liquid to the shredder material.

5. A process as defined in claim 3, including the steps of crushing the material prior to shredding and delivering juice thus removed to the collected liquid for sucrose extraction.

6. The process of claim 5, including the additional step of applying some juice obtained from the pressing operation as maceration liquid to the shredding step.

7. A process as defined in claim 1 including the step of conveying the material discharged from said press in a substantially uniform bed to a second press, and substantially saturating the material fed into the second said press with a flow of maceration liquid including recirculated liquids expressed from the material in said second press,

8. A process as defined in claim 7 including the step of adding fresh maceration water to the liquid applied to the bed of material conveyed to said second press.

9. A process as defined in claim 8 including the steps of collecting the excess maceration liquid which filters through the bed of material conveyed to said second press, and directing the excess liquid to the last drainage section of the first press.

10. Apparatus for treating sucrose bearing cellular fibrous material, such as raw sugar cane or sugar cane bagasse, to remove a high percentage of juice therefrom, comprising means mechanically working the material to rupture cells therein,

a mechanical screw press including a plurality of sequentially arranged drainage cage sections and a rotatable shaft extending through said cage sections having worm members mounted thereon to work and press the material continuously and simultaneously to carry the material sequentially through said cage sections,

a first conveyor carrying the material from said working means to said press,

means associated with said conveyor for substantially saturating the material with maceration liquid to obtain effective penetration of the liquid into the ruptured cells,

injector means in said cage sections for discharging maceration liquid into the body of material being worked and conveyed through the press by said worm members,

means associated with said cage sections for separately collecting liquid expressed from the material in the individual cage sections,

pump means connected between the respective said collecting means and the injector means of the preceding cage section to recirculate the liquid extracted in the individual cage sections in countercurrent fashion through the material being conveyed through said cage sections, and

further pump means connected to receive liquid from the first of said cage sections and supply it to said saturating means.

11. Apparatus as defined in claim 10, wherein said mechanical working means is a shredder, and means supplying maceration liquid to said shredder with the fibrous material.

12. Apparatus as defined in claim 10 including means associated with said conveyor for forming thereon a bed of material having substantially uniform thickness, said saturating means including means for directing a flow of the liquid through said bed of material, andmeans for collecting the liquid filtering through said bed for subsequent removal of sucrose.

13. Apparatus as defined in claim 10 including a second screw press, a second conveyor receiving the material discharged from the first press and feeding a uniform bed of material into said second press, and means for recirculating at least a portion of the liquid removed by said second press into the material in said second conveyor.

14. Apparatus as defined in claim 13 including means for collecting the liquid filtering through the material in said second conveyor, and means for directing such collected liquid into the last cage section of said first press.

15. Apparatus as defined in claim 14 including means for directing a fiow of fresh maceration water through the material in said second conveyor for displacing maceration liquid having a higher concentration of sucrose from the bed of material fed into said second press to obtain maximum removal of juice with said second press. 

2. A process as defined in claim 1 wherein said step of pressing includes pressing the material with progressively increasing pressure within each successive dewatering stage of the mechanical screw press.
 3. A process as defined in claim 1 wherein the maceration liquid applied to the shredded material is that liquid collected from the initial drainage cage sections of the press.
 4. A process as defined in claim 3 including the step of crushing the material prior to said shredding and thus removing an initial portion of juice from the material, and applying such initially removed juice as maceration liquid to the shredder material.
 5. A process as defined in claim 3, including the steps of crushing the material prior to shredding and delivering juice thus removed to the collected liquid for sucrose extraction.
 6. The process of claim 5, including the additional step of applying some juice obtained from the pressing operation as maceration liquid to the shredding step.
 7. A process as defined in claim 1 including the step of conveying the material discharged from said press in a substantially uniform bed to a second press, and substantially saturating the material fed into the second said press with a flow of maceration liquid including recirculated liquids expressed from the maTerial in said second press.
 8. A process as defined in claim 7 including the step of adding fresh maceration water to the liquid applied to the bed of material conveyed to said second press.
 9. A process as defined in claim 8 including the steps of collecting the excess maceration liquid which filters through the bed of material conveyed to said second press, and directing the excess liquid to the last drainage section of the first press.
 10. Apparatus for treating sucrose bearing cellular fibrous material, such as raw sugar cane or sugar cane bagasse, to remove a high percentage of juice therefrom, comprising means mechanically working the material to rupture cells therein, a mechanical screw press including a plurality of sequentially arranged drainage cage sections and a rotatable shaft extending through said cage sections having worm members mounted thereon to work and press the material continuously and simultaneously to carry the material sequentially through said cage sections, a first conveyor carrying the material from said working means to said press, means associated with said conveyor for substantially saturating the material with maceration liquid to obtain effective penetration of the liquid into the ruptured cells, injector means in said cage sections for discharging maceration liquid into the body of material being worked and conveyed through the press by said worm members, means associated with said cage sections for separately collecting liquid expressed from the material in the individual cage sections, pump means connected between the respective said collecting means and the injector means of the preceding cage section to recirculate the liquid extracted in the individual cage sections in countercurrent fashion through the material being conveyed through said cage sections, and further pump means connected to receive liquid from the first of said cage sections and supply it to said saturating means.
 11. Apparatus as defined in claim 10, wherein said mechanical working means is a shredder, and means supplying maceration liquid to said shredder with the fibrous material.
 12. Apparatus as defined in claim 10 including means associated with said conveyor for forming thereon a bed of material having substantially uniform thickness, said saturating means including means for directing a flow of the liquid through said bed of material, and means for collecting the liquid filtering through said bed for subsequent removal of sucrose.
 13. Apparatus as defined in claim 10 including a second screw press, a second conveyor receiving the material discharged from the first press and feeding a uniform bed of material into said second press, and means for recirculating at least a portion of the liquid removed by said second press into the material in said second conveyor.
 14. Apparatus as defined in claim 13 including means for collecting the liquid filtering through the material in said second conveyor, and means for directing such collected liquid into the last cage section of said first press.
 15. Apparatus as defined in claim 14 including means for directing a flow of fresh maceration water through the material in said second conveyor for displacing maceration liquid having a higher concentration of sucrose from the bed of material fed into said second press to obtain maximum removal of juice with said second press. 